Well, okay, insisting on 100% accuracy is unrealistic for anyone. That's not even an acceptable thing in most adult occupations (obviously air traffic controllers, hostage negotiators, and neurosurgeons are excused now

).
While it may be true that "error-free" is within the grasp of someone who has a fast processing speed (because they can afford do the assigned task two or even four times over?) that kind of encourages an unhealthy set of OCD-like behaviors, first of all. How many times SHOULD one check over that written paragraph for grammatical errors? How many times is enough reworking of that physics problem?